Old local newspaper archives would be a good place, our local library has our ones microfiched.
The national archive at Kew and county archives might have information.
Contact the sqns and see if they have anything.
Put an article in the local press to see if anyone has anything. Some of the original cadets might still be around, into their 90s, but you never know.
I remember asking HQAC about my squadron’s history and got the sound of wind with pictures of tumbleweed blowing through empty streets. They didn’t even have a list of squadron commanders. Bloody useless.
My old sqn was an ADCC unit and the committee had minutes and newspaper articles going back decades and the OC and former staff and committee did a really good history for the Corps’ 50th but when I went to a 70th squadron anniversary bash, I asked the current OC about the history and showed very little interest. It seems he didn’t like people harping on about the squadron’s past and showed little interest in the photos me and some of my old mates took along. If there was ever a time that I wished I’d kept track of the one I had. All the old people had either died or moved away in the interim.